from others. The plants throve, and the fruit was abundant and filled out, but when half ripe they began to dry up, and not one
produced perfect seeds. His communication on this subject is dated December 28, 1691." The importance of his discovery was not recognized at the time, and his conclusions were accepted in a figurative sense only. Not until the end of the following century was his experimental evidence used as a basis for further researches by Kölreuter. Linnæus, to whom great credit is given by many writers for his share in the development of the theory of the sexuality of plants, ignored the facts disclosed by Camerarius, and arrived at identical conclusions in a purely deductive manner, arguing from the necessities of the case.
After the demise of Camerarius he was succeeded by his son Alexander. Later the lectures on the subjects of botany and chemistry were given by one professor. After a short interregnum the subject was once more in the hands of a master spirit in the person of Joseph Gaertner, who was called to the chair of botany in 1760. Gaertner remained at Tübingen eight years, going to St. Petersburg to accept the chair of botany in 1768. He returned to Calwe in 1770, and published shortly afterward his De Fructibus et Seminibus Plantarum, which may be truly termed an epoch-making work. The study of fruits and seeds had languished for more than a century, and Gaertner came to it with a mind singularly free from prejudice. He was aware of the real value of fruits for the arrangement of plants in a natural system, but he did not attempt to found a system on such material alone. Having at hand a most extensive collection of plants from around the world, which he studied with a persistence that brought him nearly to blindness, his book is an inexhaustible mine of facts and a guide to the morphology of fruits and seeds. His collection of material and microscope are still preserved in the botanical museum.
The lectures in botany at the university were placed in the hands of Friedrich von Kielmeyer as professor of natural phi-
